Phenotypic and Cytological Characterization of Induced Tetraploid, Perennial Sorghum bicolor x S. propinquum Hybrids
Abstract
The development and use of perennial alternatives to annual crops can help alleviate some of the challenges facing agriculture. Perennial sorghum has the potential of being a low maintenance, drought tolerant, high yielding forage or bioenergy crop.
A novel induced tetraploid (2n=4x=40), interspecific Sorghum bicolor (L.) Moench (annual) x S. propinquum (Kunth) Hitchc. (perennial) hybrid’s progeny was characterized in the F₂ and F₃ generations.
Field trials were performed to determine their overwintering ability and evaluate various agronomic and morphological traits. The interspecific tetraploid population overwintered well in one evaluation environment (60-85%) and had promising yield potential. Tetraploid entries were intermediate to the parents for most morphological traits. Flowering in the tetraploid was mostly short-day photoperiodic - similar to S. propinquum. Some tetraploid individuals expressed positive transgressive segregation for plant height. Selections can be made for further breeding within the overwintered population based on forage or bioenergy characteristics.
The fertility and cytological behavior of the induced tetraploid S. bicolor x S. propinquum hybrid and its progeny were studied. The meiotic chromosome pairing behavior in these plants was relatively regular with an average of 0.45 univalents, 17.77 bivalents, 0.02 trivalents, and 0.98 quadrivalents per cell. Pollen stainability and seed set were lower than either diploid parent, but sufficiently high that the tetraploid hybrids can be propagated with seed. This germplasm has the potential of being developed into a commercial noninvasive perennial sorghum.
Subject
Sorghumperennial
tetraploid
bicolor
propinquum
interspecific
overwintering
photoperiod
forage
bioenergy
cytology
cytogenetics
PMC
pollen mother cell
microspore
chromosome pairing
Citation
Porter, Nick Taylor (2020). Phenotypic and Cytological Characterization of Induced Tetraploid, Perennial Sorghum bicolor x S. propinquum Hybrids. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /192601.